'Go' and 'come' just indicate direction. 'Come' indicates movement towards the speaker, and 'go' indicates movement away from the speaker (or to somewhere where the speaker isn't). Ex. Go there. Come here. You can't say "go here" or "come there".

Strictly speaking they can be interchangeable depending on the context of the sentence a sample below Johnny says "I want to go back to Disneyland soon" The Disneyland employee says "please come back and visit soon" Joihnny says "I will come back one day" they all mean return to Disneyland

go back -- the direction is away come back -- the direction is towards here

Go back - go away ( Do not come again ) Come back - come soon ( expecting your presence ) Not sure About the answers